BANDAR SERI BEGAWAN, BRUNEI —
U.S. Secretary of State John Kerry says China is taking "firm steps" to convince North Korea to give up its nuclear weapons program. Kerry met with foreign ministers from China, Japan, and South Korea at a forum of South East Asian nations, where officials also discussed details of a U.S. surveillance program leaked by a former intelligence analyst.

South Korean Foreign Minister Yun Byung-se says international pressure is forcing North Korea to change its "game plan from brinkmanship to a charm offensive" in an effort to weaken the united front of South Korea, Japan, China, Russia, and the United States.

But he says that is not going to happen because those allies understand that common challenges require common wisdom.

"North Korea's development of nuclear weapons will never be tolerated," he said. "North Korea's simultaneous pursuit of nuclear and economic development is not palatable and thus doomed to failure. North Korea will face further isolation and dire consequences in the event of provocations."

The South Korean foreign minister met with Secretary Kerry and Japanese Foreign Minister Fumio Kishida following Kerry's talks with Chinese Foreign Minister Wang Yi at this meeting of the Association of South East Asian Nations, or ASEAN. Kerry says Washington, Seoul, Tokyo, and Beijing are determined to convince Pyongyang to give up its nuclear weapons.

"All four of us are absolutely united and absolutely firm in our insistence that the future with respect to North Korea must include denuclearization. China made it clear to me they have made very firm statements and very firm steps that they have taken with respect to the implementation of that policy," he said.

Kerry says North Korean leaders need to understand there is a better path open to them.

"The region will be better with the denuclearization. And the possibilities of normal relationships not just between the South and the North or China and North Korea but between the United States and North Korea and the rest of the world lies at the end of engaging in a serious set of steps to denuclearize," he said.

In his talks with the Chinese foreign minister, Kerry says they discussed the case of former U.S. intelligence analyst Edward Snowden, who was allowed to leave Hong Kong for Moscow after the United States had requested his extradition on charges related to his leaking details of U.S. surveillance of telephone and Internet records.

Earlier on this trip, Kerry spoke of "consequences" for China and Russia helping Snowden avoid U.S. justice. Now he says those concerns must be balanced against cooperation on other issues including maritime disputes in the South China Sea.

"The Obama administration believes that our friends in China could in fact have made a difference here, but we have a lot of issues that we are dealing with right now," he said.

Information leaked by Snowden includes allegations that the United States listened in on conversations by members of the European Union. Kerry says EU foreign policy chief Catherine Ashton asked him about that during their talks at this ASEAN forum, and he told her he did not know anything about it because he has been so tied up with Middle East peace efforts.

Kerry says he promised to find out the truth and get back to her, offering reporters a broad defense of the surveillance program, saying it is "not unusual for lots of nations" to "undertake lots of activities to protect national security, and all kinds of information contribute to that."